IDE-SD adapter question

W2HX w2hx at
Sat Jun 27 10:34:10 CDT 2020

Peter and Maciej. Thank you very much for the input. I don't believe this BIOS supports anything other than CHS. At least I don't see a way to toggle between CHS and LBA. Is this what I should be looking for? An option to enable LBA mode?

I am not opposed to going to CF, but I have no other computers that have a CF port, thus I have no way to move files onto this 486 computer. 

Is there anyway to add LBA mode to this machine? A new BIOS? A new ISA card? 
Or am I better off considering a new motherboard altogether? Maybe more of a project than I was hoping for...

I guess a possible solution might be IDE-CF card for the 486 and maybe a corresponding USB-CF for my daily PC for file transfer?


-----Original Message-----
From: cctech <cctech-bounces at> On Behalf Of Peter Corlett via cctech
Sent: Friday, June 26, 2020 6:15 PM
To: General Discussion: On-Topic Posts <cctech at>
Subject: Re: IDE-SD adapter question

On Fri, Jun 26, 2020 at 09:39:57PM +0000, W2HX via cctech wrote:
> Thanks for previous help on this project. I am working on an old 486 
> computer and I have replaced a 40 pin IDE hard drive with this SD adapter...
> e_o01_s00?ie=UTF8&psc=1
> Question 1: Now that I am using an SD card instead of an IDE drive, 
> what, if anything, should I be doing with these BIOS parameters?

The description of that adaptor says "Attention: Some of the mother board required to enable LBA mode and disable DMA transfer mode." This suggests to me that it does not support CHS addressing, and as the Engrish says, you need to use LBA mode instead.

If your motherboard only supports CHS, you're likely to have a hard time getting many of these cheap adaptors to work with it. You might have better luck with Compact Flash, since the adaptors are passive and the CHS/LBA support (or lack thereof) is a function of the card, which is liable to be of better quality.

More information about the cctalk mailing list